In the field of off-shore hydrocarbon transport via underwater pipelines, it has been found that the underwater pipelines are susceptible to leaks and therefore the release of hydrocarbons into the body of water. It is desirable to detect leaks as soon as possible to avoid significant spillage of hydrocarbons into the body of water and severe damage to the underwater environment.
Among the various known types of underwater pipelines, the so-called flexible ‘risers’ with flanged joints are those that show a relatively greater tendency of being susceptible to leaks on the flanged joints.
Known systems for detecting leaks in pipelines installed in a body of water comprise ROVs (Remote Operated underwater Vehicles) equipped with various types of sensors to detect possible leaks during periodic inspections along the underwater pipeline.
One type of sensor used for detecting hydrocarbon leakage in a body of water is the so-called ‘sniffer’, which can be mounted on ROVs or buoys immerged at different depths in the body of water.
The foremost critical aspects of certain of the known art that contemplates the use of sensors mounted on ROVs or buoys consists in that it only allows detecting leaks after a considerable amount of time and with scarce precision, the point of the leak on the underwater pipeline not being readily identifiable. Furthermore, the hydrocarbon detection sensors lack effectiveness in locating small leaks in the open sea, which is notoriously subject to currents that disperse and dilute the hydrocarbons in the body of water. It follows that the currently known leak detection systems are untimely and rather imprecise in locating leaks.
Japanese Patent Document No. 61-139,737 discloses an apparatus for preventing leakage from a flange joint and comprising a detector for detecting the leakage of the fluid and a recovery apparatus for recovering the leaked fluid. However, this apparatus will be hardly adaptable to operate under the high pressure and the severe conditions in the underwater environment.